Metering apparatus for oxygen tents



July 21, 1953 J. GILROY ETAL METERING APPARATUS FOR OXYGEN TENTS FiledMarch 23, 1951 ERS FER HIN v INVENTORS JOHN GILROY YARTHUR R. wussz m.

ATTORNEY ratus under normal conditions.

Patented July 21, i953 L were UNITED STATES PATENT OFFICE METERINGAPPARfiATgS FOR OXYGEN John Gilroy, Sun Prairie, and Arthur R. Wiese,Jr., Madison, Wis., assignors to Air Reduction .Company, Incorporated,a. corporation of New York Application March 23, 1951, Serial No.217,201

4 Claims.

ratus be quickly and simply operated for such use.

In apparatus for delivering oxygen to hospital oxygen tents, forinstance, the oxygen is normally metered'into the tent in a range ofrelatively low gas flows suflicient to meet the demands of the patient.However, the tent enclosure containing the isolated atmosphere breathedby the patient must first be purged to bring the oxygen content tothe'required concentration before the tent is ready for use; and it isdesirable to eiiect the purgingat a relatively high rate of flow to savethe time and effort of the attendant. Usually, valve "connections of asuitable character are provided to permit oxygen to be delivered intothe tent at precisely controllable rates, meeting the needs of thepatient and also at higher rates for purging the tent preparatory to'its use; e

For safe and efiicient operation, such valve means should be simple tomanipulate and capable of rapid adjustment to deliver the gas in anormal flow range or at considerably higher flow rates above such arange. V

Oneof the objects of this invention is to provide an improved meteringapparatus for medical oxygen tents.

Another object of this invention is to provide a combined metering andflushing valve of improved'construction for use in such gas meteringapparatus, having a single control for selectively operating the valvein a range of relatively low, precisely adjustable gas flows, or in arange of Another object of the invention is to provide a valve whereinthe delivery of the high or flush rates of gas flow occurs immediatelyand automatically substantially when the valve is adjusted for themaximum rate of flow in the metered low flow range of normal use; andsubstantially without additional manipulation of the valve control meansor a separate controladjustment.

Another object of the invention isto provide is adapted to be used in agas metering apparatus assembly including a flow measuring instrument ofthe Bourdon gage, or pressure type.

A further object is to provide a valve having an improved constructionparticularly adapted to simplify maintenance and repair during service.r i a A still further object is to provide a valve of simple andinexpensive construction.

Other objects and advantages will be apparent from the specification andclaims, andfrom the accompanying drawing which illustrates a preferredembodiment of the invention.

In the drawing,

Figure 1 is an assembly view showing a pressure regulating device and animproved metering valve attached thereto which are operatively connectedto a hospital oxygen tent that is schematically illustrated in thedrawing,

Figure 2 is an enlarged sectional View of the metering valve included inthe assembly of Figure 1, and i Figure 3 is a sectional view of aportion of the metering valve taken along the line 33 in Figure 2.

In accordance with the preferred embodiment of the invention, apparatusfor delivering gas at larged opening in by-pass relation thereto, and

a valve member normally closing the enlarged bypass opening which isadapted to be opened by the pressure of the gas acting thereon, at apredetermined rate of gas flow through the metering orifice.

Referring to the drawing, an oxygen tent hood is shown schematically at[0 which is made of some suitable transparent material, such as a clearVinylite plastic, suspended above a hospital bed H by conventionalapparatus so that the lower endsof the hood maybe tucked under the bedmattress to form an enclosure. The oxygen tent may be, for example, theone disclosed in the co-pending application of J. Gilroy and P. Eckman,Serial No, 217,202, filed March 23, 1951, entitled Oxygen Tent, andassigned to the assignee of the present application; or it may besubstantially similar to the apparatus shown and described in Patent No.2,104,589, issued J anuary 4, 1938, for Refrigerating Apparatus. Suchtents comprise a bedside base for suspending the tent hood over the bed,air conditioning apparatus for circulating and cooling the atmospherewithin the enclosure formed by the tent hood, control devices therefor,and means for receiving and controlling the administering of oxygen intothe tent enclosure to meet the needs of the patient. In the presentapparatusoxygen is supplied from a source such as the oxygen cylinder !2which receives the inlet connection !3 of a pressure regulating deviceit. The regulating device is connected through its outlet boss to ametering valve is secured therein. Oxygen is delivered therefrom at adesired rate of flow through a hose H which is received over the nut 36and the back of the valve seat at the terminal end of upper chamber 30whereby the enlarged head of the valve stem is drawn into seatedengagement with the valve seat around the lower opening of passage 3i.The sectional view ofFigure3 illustrates the shape of the nut 36 whichis square so that spaces 36' are created between the longitudinal facesof the nut and the wall of the chamber 30 through which gas may passaround the nut to the valve outlet. A slot 31 is formed in the enlargedhead portion at the lower end of the valve stem 32 which may be engagedby a tool such as a screw-driver for the outlet of the metering valve atone end and entering directly into the tent hood ii! at its other end.It will be understood, however, that the oxygen delivery hose I? wouldin most instances be received in some other portion of the oxygen tentapparatus such as in the air conditioning system from whence the oxygenwould be administered to the tent enclosure instead of directly thereinas illustrated, but such associated apparatus have not been shown sincethey form no part of the'present invention, and for the purpose of thepresent invention the oxygen may be introduced into the oxygen tent inany suitable manner.

The pressure regulator M consists of a device adapted to receive gasfrom a source which may vary in pressure and deliver the gas at asubstantially constant pressure. It may be, for example, a device suchas the pressure regulating device shown and described in Patent No.1,948,027, G. M. Deming, for Compound Gas Pressure Regulator. Thus theregulator M has an adjusting handle l8 by which the regulating mechanismmay be adjusted to produce a desired delivery pressure which ismaintained substantially constant by the pressure responsive regulatingmechanism. The rate of flow of the gas through the metering valve isindicated on a gage 19, which is a pressure responsive gage of theBourdon type, secured in the regulator outlet boss, and calibrated toindicate the rate of flow.

The metering valve 16, shown in the enlarged sectional view of Figure 2,comprises an elongated valve body having a threaded portion 2l which isreceived in the outlet l5 of the pressure regulator. On the valve body ahexagonally shaped section 22 accommodates a tool for tightening theengagement of the threads 2|, and a lower cylindrical portion 23 ofreduced diameter receives the hose ll which slides onto such portion ofthe valve over the discharge outlet, forming a frictionally retainedgas-tight connection between the hose and the valve.

A passage 25 extends through the valve body, opening at one end into achamber .26 in the regulator outlet 15 and terminating at its other endin a discharge opening 21. A valve seat 28 is retained in the valvepassage against a shoulder 29 dividing the passage into an upper chamber30 and a lower chamber 30'. A longitudinal passage 3| is formed in thevalve seat between the two chambers in which a valve stem '32 isreceived; An enlarged head 33 at the lower end of the valve stem isprovided with a tapered face adapted to engage the annular lip formedaround the lower opening of the passage 3|. A coil spring 34 is carriedon the upper portion of the valve stem projecting through the valve seatinto the upper chamber 30 which is also provided with threads 35 thatreceive a spring retaining nut 36. The coil spring is compressed betweenis shown, for the sake of convenience,

moving the hose ll.

threading the valve stem into the retaining nut and thus adjusting thecompressive seating force of the valve spring. The slot 3'! is madeaccessible through the valve outlet 21 by simply re- During theadjusting of the retaining nut on the valve stem, frictional resistancenormally prevents the nut from turning with the valve stem so that theadjustment may be made without removing the valve 16 from the regulatoroutlet. To insure that the nut will not turn, a slight protrusion (notshown) may be provided on the wall of the chamber to act as a stopagainst rotation, but which will not impede longitudinal movement of thenut along the valve stem.,

The valve seat 28 is preferably made of nylon, which is a materialhaving the desired resilience to afford a gas-tight valve seatingsurface, and sufiicient strength for the purposes of the invention. Theseat is in the form of a cylindrical bushing in which a portion ofreduced outer diameter 38 forms an annular space 39 between the bushingand the bore of the lower chamber 39 which opens directly into the valvedischarge outlet. A small opening 40 constituting a metering orifice,extends substantially radially between the annular space 39 and the gaspassage 3! at the upstream side of the closed end of passage 3!. Thusthe orifice 40 is an open route for gas delivered to the inlet end ofthe valve in chamber 30, around the closed terminal opening of passage3| to the lower chamber 30 and discharge outlet Zl.

The portion 23 of the valve body on which the delivery hose I? isreceived, is provided with opening 41. The valve seat is positioned whenit is pressed into the valve body for securement therein, so that themetering orifice 40 registers with the opening M as shown in thedrawing. Thus the orifice is accessible for removal of dirt or otherflow-obstructing material that may lodge therein, without dismantlingthe valve. A simple tool, such as a small drill, may be used by removingthe hose conduit I! allowing the tool to be inserted into the orificethrough the opening 4|.

In the operation of the apparatus described, the control handle l8 ofthe regulator is adjusted for delivery of the desired pressure to themetering valve. The gas flow through the apparatus and therefore thefiow delivered to the oxygen tent is the rate at which the gas ismetered through the valve Hi. This flow is determined by the regulatorpressure supplied to the inlet side of the valve by the regulator andthe prevailing pressure at the downstream side of the valve, i. e., thepressure drop across the metering orifice. Since the tent hood for mostpurposes is at, or near, atmospheric pressure so that the downstreamside of the valve is always substantially at atmospheric pressure, thegas flow is determined wholly by the pressure of the gas administered tothe inlet of the metering valve. Thus the adjustment of the regulatorhandle 18 forv administering the gas at desired pressures to themetering valve controls the rate of flow of the gas. The flow gage i9 iscalibrated with respect to such pressures to indicate the rate of flow.

During the operation of the apparatus in the normal gas flow range thehead portion 33 on the valve stem is retained by the valve springagainst the valve seat so as to close the terminal opening of thepassage 3|. The gas then passes entirely through the metering orificewhich, because of its small flow area, enables a sensitive control ofthe gas flow rate by adjustment'of the regulator control handle. Whenthe control handle is turned to the position corresponding substantiallyto the maximum rate of fiow in the range of normal usage the gaspressure acting.

controlhandle has been adjusted so that'the flowis'increased slightlyabove 13'liters/min., the pressure acting on the valve member will besufficient to unseat the valve head portion of the valve stem from thevalve seat, whereupon a much greater flow of about 150 liters/min. isautomatically administered to the oxygen tent Without furthermanipulation of the control on the valve stem is sufficientto overcomethe seating force of the valve spring 34 causing the valve stem headportion to be unseated from the valve seat around the opening ofthe'passage 3|. Thus, in addition to the metering orifice, the

cross-sectional area of the larger passage 3| is described.

To illustrate the improved utility of the gas metering apparatus,suppose there is to be a patient committed to the oxygen tent l I fortherapeutic treatment. The regulator adjusting handle is manipuated todeliver gas through the metering valve to the oxygen tent. The nominalrange of normal use for the apparatus shown and described is from fiveto thirteen liters/min. The regulator delivery pressure corresponding tothe flow of five liters/min. is approximately 7.75 p. s. i. and thepressure corresponding to the how of 13 liters/minis 37 p. s. 1. Thusthe regulator a-djusting handle is adjusted to deliver the gas to thevalve 16 at pressures corresponding to the desired rates of flow withinthis normal range. The flushing flow is from 150 liters/min. to 200liters/- min. and this flow commences when the regulator deliverypressure is set for approximately 42 p. s. 1. Thus the flush flow is setto commence at a slightly higher flow than 13 liters/min. and

'- the low flow range is therefore extended a small amount above therate of 13 liters/min. This is done to establish a slight pressuredifferential between the regulator pressure corresponding to the flow of13 liters/min. and the pressure corresponding to the flushing flow of150 liters/min. The necessity for increasing the regulator deliverypressure by this amount prevents the possibility of delivering aflushing rate of flow when the regulator is intended to be set for arate of 13 liters/min. The low flow range is represented on the scaleIQ" of the flow indicating gage l9 by the portion of the scale havingspaced'markings corresponding to the adjusted flows, and the range offlushing rates of flow is represented by the heavy line labelled Flush.The last marking of the calibrated scale for the low fiow rangecorresponds to 13 liters/min. which it will be seen is separated by asmall intervening space from the flush zone. At first the operator willturn the regulator handle to increase the flow up to the top of the lowfiow range. When the regulator handle. The interior of the oxygen tentis purged at the flushing fiow until the oxygen concentration issufiicient for use. trol handle is turned in the direction to decreasethe flow, the pressure on the valve stem head portion is reseated on thevalve seat automatically reinstating the metering valve for deliveringprecisely controllable oxygen flows in the normal range according to therequirements of the patient. apparatus may be quickly and easilyoperated to increase the rate of delivery above the normal range ofoperation and also, in the reverse, may be readily operated to reducethe flow from a high rate to the normal low flow range. Moreover,

the improved apparatus is capable of controlling the flow of oxygen in aprecise manner.

The invention, of course, is not limited to the specific embodimentsherein illustrated and rle scribed, but may be used in other wayswithout departure from its spirit as defined by the following claims.

We claim:

1. Apparatus for metering oxygen to an oxygen,

tent comprising, anoxygen tent enclosure, a source of oxygen, a pressureregulator connected to said source for delivering oxygen at a regu-'lated metering pressure to a metering valve connected to the deliveryside of said regulator, said valve having a small opening and a largeopening in parallel-flow relation, means associated with said regulatorfor adjusting said metering pressure, means responsive to changes insaid adjusted metering pressure for automatically causing oxygen to bedelivered solely through said small opening or through both of saidopenings of said metering valve in accordance with the value of saidmetering pressure, and means for conducting the oxygen passing .throughsaid metering valve opening or openings to said oxygen' tent enclosure.

; 2. Apparatus. for metering oxygen to an oxygen tent comprising anoxygen tent enclosure, a source of gas, a pressure regulator connectedto said source for delivering oxygen at a regulated metering pressure toa metering valve connected to the delivery side of said regulator, apressure control handle for adjusting said metering gas pressure, firstand second valve openings in said metering valve disposed in parallelgas flow relationship, said first opening being of relatively smallcross-sectional area and said second opening being of relatively largecross-sectional area, pressure responsive means associated with saidsecond opening normally seated thereagainst to close said opening, saidpressure adjusting handle being adapted to control the fiow through saidfirst opening by the adjustment of said metering gas pressure, saidpressure-responsive means being adapted to be unseated from said secondopening by gas pressure corresponding to a predetermined rate of flow ofthe gas through the first opening, and gas conduit means for deliveringthe oxygen from said metering valve to said enclosure whereby the gasflow to said enclosure may be precisely adjusted at any selected flowrate through said first opening within a normal When the con- It willthus be seen that the gas metering v 7 range of flows by adjustment ofsaid regulator control handle and is automatically delivered to saidenclosure at a much greater rate when the regulator control handle isadjusted to a position'corresponding substantially to the maximum flowin said range.

3. A valve for metering gases comprising an elongated valve body havingan inlet and an outlet at the opposite ends thereof, a threaded portionat the inlet end enabling said valve body to be secured in a gasadministering instrument, a cylindrical portion at the outlet end foraccommodating a gas conduit which is adapted to be frictionally retainedin a gas-tight manner thereon, a valve seat in the valve body, first andsecond chambers on opposite sides thereof communicating respectivelywith the valve inlet and outlet, said valve seat being'longi'tudinallyelongated and having a relatively large diameter passage extendingtherethrough between said first and second chambers, a valve membersmaller than said passage extending substantially centrally through saidpassage, an enlarged head portion at one end of said valve memberadapted to be seated against the terminal end of said passage in saidsecond chamber, the other end of said valve member extending into saidfirst chamher, an adjustable retaining nut thereon, a spring compressedagainst said retaining nut urging said head portion into engagement withsaid valve seat, means for adjusting the compression of said valvespring, an annular space between said valve body and a cylindricalportion of said valve seat, said space communicating with said secondchamber, a cross passage inthe valve seat of relatively smallcross-sectional area extending substantially radially of the axis ofsaid valve and the valve seat between said relatively large passage andsaid annular space, said cross passage enabling gas to be meteredtherethrough at rates dependent upon the pressure differential betweenthe valve inlet and outlet, said head portion being adapted to beunseated from said valve seat at a predetermined pressure differential,and an opem'ng in said cylindrical portion of the valve body in registerwith said passage of relatively small cross-sectional area adapted toenable the insertion of a cleaning tool therethrough into said crosspassage, said opening being effectively sealed by the gas conduitreceived thereon.

4. A valve for metering gases comprising an elongated valve body havingan inlet and an outlet at opposite ends thereof, a valve bore extendingbetween said valve inlet and outlet, a shoulder in said bore, acylindrical bushing positioned against said shoulder forming a valveseat, a portion of reduced diameter at the outer end of said cylindricalvalve seat bushing forming a space the-rearound in said valve bore, alongitudinal valve passage through said valve seat bushing, a lateralmetering passage in said bushing connecting said valve passage and saidspace, an elongated valve element extending through said valve passage,one end of said valve element having an enlarged head portion engageablewith said valve seat to form a valve closure for said longitudinal valvepassage, said opposite end having a threaded retaining nutlongitudinally adjustable thereon, a valve spring compressed betweensaid retaining nut and said valve seat bushing urging said valve elementinto closed position against said valve seat, and means for adjustingsaid retaining nut and regulating the compression of said spring, saidvalve element being adapted normally to close said longitudinal passageand to be unseated from said valve seat at a predetermined rate of flowthrough said lateral metering passage.

JOHN GILROY.

ARTHUR R. WIESE, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,093,576 McNutt Apr. 14, 1914 1,774,690 Willoughby Sept. 2,1930 1,858,400 Koehler May 17, 1932 2,185,103 Heigis Dec. 26, 19392,286,713 Burks June 16, .1942

